Question 1099622
<pre>3X-9Y= 9,   3Y=X +12,   2X- 6Y= 12</pre>

Basic Rule:  slopes equal means lines parallel (unless the two lines are the same); slopes which are negative reciprocal of each other are perpendicular.


Slopes of your lines in order given:
<pre>1/3,   1/3,   and 1/3</pre>.
(Are any pair of your lines the same line?)